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  <div class="section" id="module-sndhdr">
<span id="sndhdr-determine-type-of-sound-file"></span><h1><a class="reference internal" href="#module-sndhdr" title="sndhdr: Determine type of a sound file."><code class="xref py py-mod docutils literal notranslate"><span class="pre">sndhdr</span></code></a> --- 推测声音文件的类型<a class="headerlink" href="#module-sndhdr" title="永久链接至标题">¶</a></h1>
<p><strong>源代码</strong> <a class="reference external" href="https://github.com/python/cpython/tree/3.7/Lib/sndhdr.py">Lib/sndhdr.py</a></p>
<hr class="docutils" id="index-0" />
<p><a class="reference internal" href="#module-sndhdr" title="sndhdr: Determine type of a sound file."><code class="xref py py-mod docutils literal notranslate"><span class="pre">sndhdr</span></code></a> 提供了企图猜测文件中的声音数据类型的功能函数。当这些函数可以推测出存储在文件中的声音数据的类型是，它们返回一个 <a class="reference internal" href="collections.html#collections.namedtuple" title="collections.namedtuple"><code class="xref py py-func docutils literal notranslate"><span class="pre">collections.namedtuple()</span></code></a>，包含了五种属性：（<code class="docutils literal notranslate"><span class="pre">filetype</span></code>, <code class="docutils literal notranslate"><span class="pre">framerate</span></code>, <code class="docutils literal notranslate"><span class="pre">nchannels</span></code>, <code class="docutils literal notranslate"><span class="pre">nframes</span></code>, <code class="docutils literal notranslate"><span class="pre">sampwidth</span></code>）。这些 <em>type</em> 的值表示数据的类型，会是以下字符串之一： <code class="docutils literal notranslate"><span class="pre">'aifc'</span></code>, <code class="docutils literal notranslate"><span class="pre">'aiff'</span></code>, <code class="docutils literal notranslate"><span class="pre">'au'</span></code>, <code class="docutils literal notranslate"><span class="pre">'hcom'</span></code>, <code class="docutils literal notranslate"><span class="pre">'sndr'</span></code>, <code class="docutils literal notranslate"><span class="pre">'sndt'</span></code>, <code class="docutils literal notranslate"><span class="pre">'voc'</span></code>, <code class="docutils literal notranslate"><span class="pre">'wav'</span></code>, <code class="docutils literal notranslate"><span class="pre">'8svx'</span></code>, <code class="docutils literal notranslate"><span class="pre">'sb'</span></code>, <code class="docutils literal notranslate"><span class="pre">'ub'</span></code>, or <code class="docutils literal notranslate"><span class="pre">'ul'</span></code> 。 <em>sampling_rate</em> 可能是实际值或者当未知或者难以解码时的 <code class="docutils literal notranslate"><span class="pre">0</span></code>。类似的， <em>channels</em> 也会返回实际值或者在无法推测或者难以解码时返回 <code class="docutils literal notranslate"><span class="pre">0</span></code>。 <em>frames</em> 则是实际值或 <code class="docutils literal notranslate"><span class="pre">-1</span></code>。 元组的最后一项， <em>bits_per_sample</em> 将会为比特表示的 sample 大小或者 A-LAW 时为 <code class="docutils literal notranslate"><span class="pre">'A'</span></code>， u-LAW 时为 <code class="docutils literal notranslate"><span class="pre">'U'</span></code>。</p>
<dl class="function">
<dt id="sndhdr.what">
<code class="sig-prename descclassname">sndhdr.</code><code class="sig-name descname">what</code><span class="sig-paren">(</span><em class="sig-param">filename</em><span class="sig-paren">)</span><a class="headerlink" href="#sndhdr.what" title="永久链接至目标">¶</a></dt>
<dd><p>使用 <a class="reference internal" href="#sndhdr.whathdr" title="sndhdr.whathdr"><code class="xref py py-func docutils literal notranslate"><span class="pre">whathdr()</span></code></a> 推测存储在 <em>filename</em> 文件中的声音数据的类型。如果成功，返回上述的命名元组，否则返回 <code class="docutils literal notranslate"><span class="pre">None</span></code>。</p>
<div class="versionchanged">
<p><span class="versionmodified changed">在 3.5 版更改: </span>将结果从元组改为命名元组。</p>
</div>
</dd></dl>

<dl class="function">
<dt id="sndhdr.whathdr">
<code class="sig-prename descclassname">sndhdr.</code><code class="sig-name descname">whathdr</code><span class="sig-paren">(</span><em class="sig-param">filename</em><span class="sig-paren">)</span><a class="headerlink" href="#sndhdr.whathdr" title="永久链接至目标">¶</a></dt>
<dd><p>基于文件头推测存储在文件中的声音数据类型。文件名由 <em>filename</em> 给出。这个函数在成功时返回上述命名元组，或者在失败时返回 <code class="docutils literal notranslate"><span class="pre">None</span></code>。</p>
<div class="versionchanged">
<p><span class="versionmodified changed">在 3.5 版更改: </span>将结果从元组改为命名元组。</p>
</div>
</dd></dl>

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